This invention relates to a vacuum insulating glass (IG) unit. More particularly, this invention relates to a vacuum IG unit having a plurality of micro-sized spacers disposed between opposing substrates so as to form a low pressure space therebetween.
Commonly owned U.S. Ser. No. 09/348,281 entitled xe2x80x9cPERIPHERAL SEAL FOR VACUUM IG WINDOW UNITxe2x80x9d filed Jul. 7, 1999 pending; U.S. Ser. No. 09/303,550 entitled xe2x80x9cVACUUM IG PILLAR WITH DLC COATINGxe2x80x9d filed May 3, 1999; U.S. Ser. No. 09/404,659 filed Sep. 24, 1999 entitled xe2x80x9cVACUUM IG WINDOW UNIT WITH PERIPHERAL SEAL AT LEAST PARTIALLY DIFFUSED AT TEMPERxe2x80x9d pending; and U.S. Ser. No. 09/440,697 filed Nov. 16, 1999 entitled xe2x80x9cVACUUM IG WINDOW UNIT WITH FIBER SPACERSxe2x80x9d pending, are all hereby incorporated herein by reference.
Vacuum IG units are known in the art. For example, see U.S. Pat. Nos. 5,664,395, 5,657,607, 5,891,536 and 5,902,652, the disclosures of which are all hereby incorporated herein by reference.
Prior art FIGS. 1-2 illustrate a conventional vacuum IG unit. IG unit 1 includes two spaced apart sheets of glass 2 and 3 which enclose an evacuated or low pressure space 16 therebetween. Glass sheets 2 and 3 are interconnected by peripheral or edge seal of fused solder glass 4 and have an array of support spacers/pillars 5 therebetween.
Pump out tube 8 is sealed by solder glass 9 to an aperture or hole which passes from an interior surface of glass sheet 2 to the bottom of recess 11. A vacuum is attached to tube 8 (prior to the tube being sealed) so that the interior space 16 between sheets 2 and 3 can be evacuated to create a low pressure area. After evacuation, an end of tube 8 is melted to seal the vacuum in space 16. Optionally, getter 12 may be provided within recess 13 to counteract any rise in pressure due to any out-gassing from the glass.
FIG. 3 is a side cross sectional view of another conventional vacuum IG window unit. This unit differs from the FIGS. 1-2 unit, in that its glass sheets are of different sizes so as to provide an L-shaped step around the unit""s periphery, on which edge seal 4 is to be at least partially located. Moreover, this unit includes low-E coating 6 on the interior major surface of glass sheet 3.
Conventional vacuum IG units, with their fused solder glass peripheral seals 4, have been manufactured as follows. Solder glass for seal 4 is initially deposited around the periphery of the unit. The entire assembly, including sheets 2, 3 and the solder glass material, is then heated to a temperature of approximately 500 degrees C. at which the solder glass melts, wets the surfaces of the glass sheets, and flows by capillary action into the space between the sheets so as to form hermetic peripheral/edge seal 4. After formation of seal 4, the assembly is cooled to room temperature.
Unfortunately, many conventional vacuum IG window units are aesthetically nonpleasing due to the presence of large spacers/pillars 5 which are visible to a viewer looking through the window unit. In such window units, large visible spacers in the middle of the viewing area may represent an eyesore.
It is apparent from the above that there exists a need in the art for a vacuum IG unit, and corresponding method of making the same, in which the unit is aesthetically pleasing to view. There also exists a need in the art for a VIG unit including spacers/pillars which are difficult to see with the naked eye at a normal distance from the unit (e.g., two to three feet away) where one would typically stand when looking through the window unit, while also being strong enough to maintain the space between the opposing substrates.
This invention will now be described with respect to certain embodiments thereof, accompanied by certain illustrations.
An object of this invention is to provide a vacuum IG window unit including spacers which are difficult to see with the naked eye by one looking through the window unit at a normal viewing distance.
Another object of this invention is to provide spacers for a vacuum IG window unit which may be made sufficiently small so as to be visibly unobtrusive and yet still be strong enough to support the substrates against atmospheric pressure in order to maintain the low pressure space therebetween.
Another object of this invention is to provide a vacuum IG window unit including single crystal spacers disposed between the opposing substrates.
Another object of this invention is to provide a vacuum IG unit including single crystal alumina platelet spacers disposed between the opposing substrates.
Another object of this invention is to fulfill any and/or all of the above-listed objects and/or needs.
Generally speaking, this invention fulfills any or all of the above described objects or needs by providing a thermally insulating glass panel comprising:
first and second spaced apart glass substrates defining a low pressure space therebetween having a pressure less than atmospheric pressure;
a plurality of spacers disposed between the first and second glass substrates for spacing the substrates from one another in order to maintain the low pressure space therebetween; and
wherein at least one of the spacers is a single crystal structure having a maximum thickness of from about 10 to 100 xcexcm.
This invention further fulfills any or all of the above-described needs or objects by providing a thermally insulating panel comprising:
first and second spaced apart substrates defining a space therebetween; and
at least one spacer consisting essentially of a single crystal structure provided between the substrates in order to space the substrates from one another.
This invention still further fulfills any or all of the above described needs or objects by providing a thermally insulating glass panel comprising:
first and second spaced apart glass substrates defining a low pressure space therebetween having a pressure less than atmospheric pressure;
a plurality of spacers disposed between the first and second glass substrates for spacing the substrates from one another in order to maintain the low pressure space therebetween; and
wherein at least one of the spacers includes first and second approximately parallel major flat surfaces for supporting the first and second substrates, respectively, a vertically extending peripheral surface extending in a direction approximately perpendicular to planes defined by the first and second major flat surfaces, and a first slanted surface extending between the vertically extending peripheral surface and the first major flat surface.